Same issue. Will not connect via WiFi or Internet. I am in California. Last successful login was 2300 Hours 3/8/2018. We were winning TW, entire guild has been locked out, we are 50% US based the rest in EU. The EU team has been locked out for the last 10 hours.
Using iOS 6E updated to 11.2.6. Verizon is carrier. Other Phone is iOS7 updated 11.2.6 AT&T carrier. Neither platform is allowing access.
March 2018 - last edited March 2018
iOS 10.3.2, most current app, US-based. Cannot get past loading screen with "Checking for Updates" caption. After a few minutes of this, throws up a connection error notice. Unlike last time, logging out of Game Center changes nothing.